Radiometric studies on the biosynthesis and principal metabolic pathways of estrogen and androgens in patients with breast, endometrial and prostate cancer will be continued and the results compared with those obtained in normal subjects. The impact of endocrine therapy on these transformations will be followed to determine whether any correlations exist. The properties of receptors in human breast, endometrial and ovarian tumor tissues will be explored with particular emphasis on the heterogeneity of these receptors. These differences in receptor properties will be correlated with the clinical history of the patients. Studies will be continued in the pathways of estradiol biosynthesis and on the role of its transformation products produced in situ on the biological responses observed in various target sites. The mechanisms of formation and the role of the novel cortoic acids will remain an active area of study. New methods for the quantitation of these compounds are being explored. Studies on the mechanism of entry of hormones into human breast cysts will be continued. Studies of the influence of drugs and diet on the metabolism of estradiol in normal patients will be carried out to determine the influence of these compounds on the pathways of metabolism of estradiol in order to seek a relationship between diet or drugs and cancer risk.